They're a bit high poly, but Blizzard ones are too, I based these ones on Blizzard cars. They can be used in Azeroth Grand Prix. To help you here is a list of which is based in which. That will help if you're gonna use the same system than in Azeroth Grand Prix for your map.

Illidan: Diablo Car

Naga: Undead Car

Blood Elf: Undead Car

Fel Guard: Orc Car

Goblin: Undead Car

Nigh Elf: Undead Car

Panda: Dwarf Car

Firelord: Undead Car

None of these need custom textures. Give credit if you use any of them. Enjoy them!